Coinductive Proofs of Regular Expression Equivalence in Zero Knowledge

Explore a groundbreaking conference presentation introducing Crepe, the first zero-knowledge protocol for proving regular expression equivalence without revealing the underlying programs. Learn how this innovative approach tackles the PSPACE-complete problem of demonstrating that two regular expressions are equivalent, addressing a gap in existing zero-knowledge protocols that previously only handled individual string matching. Discover the custom calculus of proof rules based on regular expression derivatives and coinduction that enables this breakthrough, along with the sound and complete algorithm developed for generating proofs in this novel format. Examine the practical implementation and performance results from testing on hundreds of regular expression equivalence proofs, demonstrating validation of large proofs in just seconds. Understand the theoretical foundations and real-world applications of this first zero-knowledge protocol to successfully target a PSPACE-complete problem, with implications for software verification where developers need to prove program correctness without exposing proprietary code. Access comprehensive supplementary materials including artifacts and reproducible results that support the research findings presented by the Yale University team at the OOPSLA 2025 conference.